Large diameter well-drilling bit



Nov. 15, 1966 w. J- NEILSON ETAL 3,235,355

LARGE DIAMETER WELL-DRILLING BIT Filed Feb. 17, 1964 I 5 Sheets-Sheet 1 INVENTORS ATTOI/VfYS Nov. 15, 1966 w. J. NEILSON ETAL 3,285,355

LARGE DIAMETER WELL-DRILLING BIT Filed Feb. 17, 1964 5 Sheets-Sheet 2 BY WW Nov. 15, 1966 w. J. NEIL SON ETAL 3,285,355

LARGE DIAMETER WELL-DRILLING BIT 5 Sheets-Sheet 5 Filed Feb. 17, 1964 INVENTORS m w J W Nov. 15, 1966 w. J. NEILSON ETAL 3,285,355

LARGE DIAMETER WELL-DRILLING BIT 5 Sheets-Sheet 4 Filed Feb. 17, 1964 INVENTORS BY /}@ZZM ATTOR/V'KS' United States Patent 3,285,355 LARGE DIAMETER WELL-DRILLING BIT William J. Neilson and Robert L. Dixon, Whittier, Calif.,

assignors to Smith Industries International, Inc., Compton, Calif., a corporation of California Filed Feb. 17, 1964, Ser. No. 345,310 Claims. (Cl. 175-334) This invention relates to an earth-boring bit or drill designed to drill holes of large diameters such as large diameter well holes, tunnels, shafts, adits, and the like.

A primary object of the invention is to provide an earth-boring bit or drill consisting essentially of a pilot drill followed by a plurality of detachably connected stages each of which is equipped with roller cutters. Consecutive stages progressively increase in diameter and, in effect, enlarge the hole initially drilled by the pilot drill. As the stages follow the pilot drill they have some stabilizing effect which tends to retard or inhibit wandering of the pilot drill as'the drilling proceeds. However, the trailing of the stages behind the pilot drill is not so great as to prevent directional drilling if this is required.

More specifically, an object of the invention is to provide an earth-boring drill or bit having the above mentioned characteristics which will enable parts that are,

apt to become worn to be readily renewed or replaced without involving a replacement of the entire structure.

Still another object of the invention is to provide an earth-boring drill having the above mentioned characteristics which is readily adjustable at a minimum expense so that any hole diameter may be drilled within the capacity of the entire bit. In this manner much of the bit may be used for drilling any size hole and only the last stage may be required to be replaced to meet any specific requirement that the hole drilled shall have a certain specified diameter.

Another object of the invention is to provide an earthboring drill of such design that it may be adequately weighted when weighing of the drill is desirable or necessary.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

FIGURE 1 is a view in side elevation, parts being broken away and shown in vertical section of one form of earth-boring bit embodying the present invention.

FIGS. 2, 3, 4, and 5 are horizontal sections taken substantially upon the lines 2-2, 3-3, 4-4, and 5-5, respectively, on FIG. 1 in the direction indicated.

. FIGURE 6 is an excluded view showing the stages of the bit with the weighing container means of FIGURE 7 interposed in broken lines between the stages.

FIGURE 7 is a view in side elevation, parts being broken away and shown in vertical section, showing the weight that may be employed between two or more stages when weighting of the bit is required.

FIGURE 8 is a view similar to FIG. 1 illustrating an alternative form of construction.

FIGURE 9 is a sectional view taken substantially upon the line 9-9, upon FIG. 1 in the direction indicated.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved earth-boring bit consists of a pilot bit or drill generally indicated at 10 which may be of any conventional or preferred construction designed to drill holes in earth formations. This pilot drill may conform to a conventional rock bit in which roller cutters 11 are rotatably mounted on a suitable body 12 which is equipped with a pin 13 or flange 13a (FIG. 8) that is ordinarily used for attaching the bit to a drill collar at the lower end of a rotary well drilling string. This pin in the present construction is used to attach the bit to the bottom of a heavy walled central conduit 14 that forms a part of a first stage that follows the bit 10. This stage consists of the central conduit 14 and an upper frame member or plate 15. Cutter yokes 16 are equally spaced around the conduit 14 and are welded, as indicated at 17, or otherwise rigidly secured to the exterior of the conduit 14 and the underside of the frame 15. These cutter yokes serve to rotatably mount roller cutters 18 which usually have radially extending cutting teeth. The roller cutters 18 are rotatably mounted by means of bearing pins 19 which are supported at their inner and outer ends by the yokes. These bearing pins are in turn pinned in place in their respective yokes 16 such as by pins 20 which are retained in their respective holes by means of pipe plugs 21 as shown in FIG. 9. Anti-friction bearings, not shown, may be interposed between the bearing pins 19 and the roller cutters 18. Tubes 22 are welded or otherwise secured to the central conduit 14 and communicate with the interior of the conduit. The outer ends of these tubes are directed so as to discharge circulation fluid against the formation adjacent the roller cutters 18 to wash away cuttings produced by the disintegration of the earth formation by the cutters.

Above the first stage just described there may be one or more additional stages generally designated at 23, 24 and 25. These stages have similar constructions to each other differing mainly as to size. Thus each of the following or succeeding stages consists of a central column in the form of a conduit 26 and spaced frame members 27 and 28. Cutter yokes 29 are distributed equally about the central conduit 26 and are welded or otherwise rigidly secured to the frame members 27 and 28. They serve to rotatably mount roller cutters 30 on bearing pins 31 which are similar to the bearing pins 19 and are locked in place by locking pins similar to the locking pins 20. Tubes 32 are welded or otherwise secured to the central conduit 26 and communicate with the interior of the central conduit so as to be capable of receiving circulation fluid therefrom. These tubes have their outer ends directed downwardly adjacent the cutters 30 to wash away cuttings. Each stage may be equipped with studs 33 on the top of the upper frame member thereof. The studs 33 are receivable in holes in the lower frame member of the stage next above and cooperate with the bolts 34 to transmit torque from one stage to another. The bolts 34, however, enable any stage to be detached from the entire assembly and either be replaced by another stage or be omitted entirely when a smaller sized hole is desired. The conduits 26 in all stages being centrally located are aligned with each other when the stages are assembled together and are aligned with the conduit 14 in the lowermost stage. These conduits are also in alignment with a rotary drill stem or turning device indicated at 35 shown as having a flange 36 bolted as at 37 and studded as at 38 to the topmost stage. The drill stem 35 is rotated by any adequate source of power and weight or pressure is imposed on the entire structure causing it to penetrate the earth formation that is to be drilled. During the drilling the pilot bit 10 drills the initial hole and this is enlarged thereafter by the following cutters 18 on the first stage. Thereafter the hole is progressively enlarged by the roller cutters 30 on the succeeding stages 23, 24 and 25. During the drilling circulation fluid may be forced through the drill stem 35 and will be discharged through the body of the bit 10 adjacent cutters 11 and 3 through the tubes 22 and 32 adjacent the cutters 18 and 30, respectively.

Should any cutter 18 or 30 become worn and require replacement, this can .be rather easily accomplished by unscrewing the pipeplug 21, withdrawing the pin 31, and withdrawing the bearing pin 19. The cutter can then be slipped from its yoke and replaced. The same method of replacement can be performed in relation to the cutters 30 on succeeding stages.

A feature of the present earth-boring drill resides in the fact that all cutters are not located on the same or substantially the same transverse plane. located some distancebehind the pilot drill 10 and, in turn, the cutters 30 of the stages 23, 24 and 25 are located some distance behind the cuttersof the preceding stage. With this arrangement the stages have some stabilizing ability tending to retard wandering of the pilot bit 10 as the drilling proceeds. However the spacing is not so great that intentional directional drilling is prevented.

A feature of the invention resides in the versatility of the design enabling parts to be largely standardized yet enablingany specified hole diameter to be secured. By way of illustration and not limitation, the following sizes and dimensions may be considered as illustrative. The cutters '18 and- 30 and their respective yokes can be made in three sizes namely, of 6" length of cutters, 9 length of cutters, and 12" length of cutters. If the p1lot bit 10 is a 24'-' bit and the cutters 18 of the first stage are 12-cutters, the'first stage will widen the 24" hole drilledby the pilot bit to a 48" hole. Similarly if the cutters 30 of stage 23 are 12" cutters they will enlarge the hole to a 72" diameter and if cutters 30 of stage 24 are 12" cutters they will enlarge the hole to 96". If cutters 30 of stage 25 are 12" cutters they will enlarge the hole to a diameter of 120". If an intermediate-size isrequired such as, for example, a 70 hole, then the upper stages 25 and 24 are detached from the assembly by the removal of bolts 34 and are omitted. A special stage'23 is then prepared which is similar to the stage 23 illustrated except that the yokes 29 aremoved inwardly between the frame members 27 and 28 prior to beingwelded in place. The inward movement to reduce the diameter from 72 to 70" need only be 1"-. The only part requiring replacement to'meet the requ rement of such a diameter hole is the replacement of the stage 23.

On th'eother hand, if the hole size diameter requires that a' yoke 29 be moved inwardly a considerable distance, interference may occur between a 12" yoke 29 and the central conduit 26. Consequently it may be necessary to employ a 9" yoke and 9" cutter or a 6" yoke and a 6" cutter in meeting a certain specified hole size.- Such an adjustment or selection of yokes and cutters can be accomplished in stages 24 or 25 as occasion requires. In all instances it will be appreciated that the remainder of the assembly need not be disturbed and that in order to meet a certain specified hole size only the largest stage need he specially constructed to meet the required diameter.

Earth-boring drills on bits designed to drill holes of such I great diameters frequently must be adequately weighted at or near the bit at the lower end of the drill string; To" accomplish adequate weighting, weight container means may be provided of the type illustrated in FIG.. 7. Each weight may consist of a central tube 40 which provides a central circulation passage 41 for circu lation' fluid. Disposed about the tube 40 is an outer op andbottom plates 43 and 44, near which thereare ,45 and 46. These end plates are heldin posir'om the spacers mane-4s and are likewise 52 and in through which a quick setting Cutters 18 are 1 casing 4 2 which is concentrically arranged with respect 0 the tub'e'40. The casing 42 is held in such relationship circular or annular spacers 47 and48, which are lace and radial g'ussets' 49fand 50 extend 1 .The uPP r plates 43 a'nd,45 have aligned cement slurry 53 may be poured to fill the space be-. tween the tube 40 and the casing 42. This cement slurry constitutes the weighting material. The structure illustrated in FIG. 7 is usually shipped empty of slurry to the well site and is filled with the slurry at the well site when a weight is desired.

It will be observed that the studs 33 and 38 on all stages are arranged on the same circle or have the same locations on their respective stages. Also the bolts 34 and 37 on all stages are arranged on the same bolt circle or have the same locations. The weight shown in FIG. 7 has the torque studs 54 and holes 55 arranged on the same circle or on the same location as the studs 33 and 38. Also the plates 45 and 46 have bolt holes arranged on the same bolt circle or on the same location as the bolt circles for the bolts 34 and 37. Consequently one or more weights as shown in FIG. 7 may specially be incorporated in the bit by being interposed between one or more pairs of adjacent stages. Holes 55 will accommodate the torque studs 33 or 38 and the studs 54 will be receivable in the holes which receive studs 33 or 38. Likewise the bolt holes in the plates 45 and 46 are capable of receiving the bolts 34 or 37 to enable the weights shown in FIG. 7 tobe specially incorporated in the bit and to detachably connect the various stages to each other.

Because ofthe fact that the hole drilled by the im* proved earth-boring drill is of such great size, the volume of circulation fluid discharged from the bit tube 22 and tubes 32 may be inadequate to have sufficient filling to carry away the cuttings. This may be particularly true in drilling vertical Wells, vertical shafts and the like.

Under such circumstances it may be desirable to reverse the direction of flow of the circulation fluid, that is, to force the circulation fluid downwardly through the bore hole and up through the drill stem 35. Sometimes eductors are incorporated in the drill stem 35 to induce reverse flow of circulation fluid and through so that the cuttings will be carried upwardly through the drill stem at relatively high velocity. To meet these requirements the alternative form of construction illustrated in FIG. 8 has been designed. This consists of a pilot drill 60 followed by a first stage 61 having roller cutters 62. The first stage has its hollow central body portion internally enlarged to provide a plenum 63 to which a tube 64 of relatively large diameter is secured so as to commu- 'outer ends of their tubes '32' a r e usually plugged with removable plugs when the succeeding stages are employed. I

' I-t will be appreciated from the above described construction that par-ts of the improved .bit can be largely stand ardized but that regardless of the standardization and with only.the modification of a single stage any exact hole size diameter may be obtained within the capacity range of the tool.

, Various changes may be made in the details of the construction without departing from the spirit and scope of the invention as defined by the appended claims.

. We claim:

,1. A large diameter drilling bit having a plurality of stages, roller cuttersrotatably mounted on each stage arranged so that the cutters on the successive stages cut on anuuli of progressively increasing diameters, and weight container means interposed between two or more stages and detachably connecting adjacent stages to each other.

2. A large diameter drilling bit having a plurality of stages, roller cutters rotatively mounted on each stage arranged so that the cutters on the successive stages cut on annuli on progressively increasing diameters and weight means interposed between two or more stages detachably connecting adjacent stages to each other, said weight means being hollow and having a central circulation passage therethrough, and weighting material filling the weight means around the circulation passage.

3. A drilling bit comprising a pilot drill and a plurality of stages detachably secured to each other and to the pilot drill behind the pilot drill, each stage comprising vertically spaced frame members and roller cutter yokes extending between and rigidly interconnecting the vertically spaced frame members of their respective stages, and roller cutters mounted for rotation on the roller cutter yokes, the cutters on successive stages being arranged on progressively increasing diameters.

4. A drilling bit comprising a pilot drill and a plurality of stages detachably secured to each other and to the pilot drill behind the pilot drill, each stage comprising spaced frame members and roller cutter yokes extending between and rigidly interconnecting the frame members, roller cutters mounted for rotation on the roller cutter yokes, the cutters on successive stages being arranged on progressively increasing diameters, and conduits connecting the frame members of each stage centrally thereof so as to be alignable with the conduits of adjacent stages.

5. A drilling bit comprising a pilot drill and a plurality of stages detachably secured to each other and to the pilot drill behind the pilot drill, each stage comprising spaced frame members and roller cutter yokes rigidly inter-connecting the frame members, roller cutters mounted for rotation on the roller cutter yokes, the cutters on successive stages being arranged on progressively increasing diameters, and conduits connecting the frame members of each stage centrally thereof so as to be aligna ble with the conduits of adjacent stages, weight means interposed between two or more stages detachably connecting adjacent stages to each other, said weight means being hollow and having a central circulation passage therethrough, and weighting material filling the weight means around the circulation passage, and circulation discharge conduits leading from the mentioned conduits arranged to discharge adjacent the cutters of their respective stages.

References Cited by the Examiner UNITED STATES PATENTS 1,375,094 4/1921 Humason 175334 2,090,356 8/ 1937 Reed 175-344 X 2,755,071 7/ 1956 Kammerer 175-334 X 3,215,214 11/1965 Caro 175-334 X OTHER REFERENCES Drilling magazine, March 19, 1963 issue, pages 64, 65 and 72 relied on.

CHARLES E. OCONNELL, Primary Examiner.

N. C. BYERS, Assistant Examiner. 

1. A LARGE DIAMETER DRILLING BIT HAVING A PLURALITY OF STAGES, ROLLER CUTTERS ROTATABLY MOUNTED ON EACH STAGE ARRANGED SO THAT THE CUTTERS ON THE SUCCESSIVE STAGES CUT ON ANNULI OF PROGRESSIVELY INCREASING DIAMETERS, AND WEIGHT CONTAINER MEANS INTERPOSED BETWEEN TWO OR MORE STAGES AND DETACHABLY CONNECTING ADJACENT STAGES TO EACH OTHER. 